So I've been doing some research on cycling. I have had a 5gal since January of this year but I've read that cycling wouldn't happen in a tank that small and that it would just be best to do water changes.

But my bf got a 10gal last week and is a total noobie (not unlike me) so I thought that maybe we could cycle this tank. Thing is, the instructions that I've found online say to use a few small fish to get it started. We only have the one betta is the 10gal and we do not intend to put any other fish in there (nor do we want to). My question is, how do we cycle a tank that already houses a betta and about 10 shrimp?

The thing is, they always recommend using other kind of fish. I only have a betta in that tank and do not want anything else in it. How do I cycle a tank with just the betta and 10 shrimp in it?? I'm so confused.

Yeah so far my Bettas have not faired well with a fish in cycle. I would recommend using the 5 gallon tank and monitoring the water parameters in it and doing a fishless cycle on the 10 gallon. This is my personal recommendation. Of course others have had Bettas and cycled tanks fine.

The thing with fish-in cycling is every fish even in the same species is going to react differently. Even in the "hardier" fishes they will sometimes lose 1 or 2 out of a school. With my Bettas I attempted a fish in cycling with I had one that almost died (got so weak he couldn't out swim the filter) and still fighting fin rot. The other guy I had developed slight fin rot that cleared up in a week with clean water. I kept the ammonia levels at .25 or below and for the first two week I kept them almost nil doing 80% water changes at the hint of ammonia. After 3 or so weeks in .25ish ammonia levels the fish developed problems. Also a fishless cycle will cycle faster than a fish in cycle as you can keep ammonia levels higher and offer the bacteria more food all at once to build the colony instead of a little at a time.

I'm not saying you have to do fishless, because I know myself was very much set on doing the fish-in cycle. I'm just giving my recommendations and trying to make it clear that with a fish-in cylce you have to watch the fish very closely. As some will have adverse reactions to even what is considered a "fish safe" level of ammonia over the extended period of a cycle.

As far as how to do it with fish in you do it the same with any other fish. Add fish and feed them lightly and watch the water parameters very closely do not disturb the filter(s) or substrate and anytime you see high levels of either ammonia or nitrite you do a water change. Some fish are recommended over others because of their reputation for being able to make it through cycles with survivors. These lucky fish get to be called "hardy". Some fish are not recommended such as ottos because of their reputation for being ultra sensitive to water conditions. Bettas fall somewhere in between hardy and ultra sensitive and aren't really recommended for or against. As far as the shrimp goes I do not know how they will take to the cycling process.

If you want to do the fish-in cycle and I understand that it's nice having the fish in the new tank all and maybe you don't space for the 2nd 5 gallon to be setup. I would watch the fish and water parameters very closely. Also be ready to put the Betta in a smaller QT tank (1-2 gallon) if he does suffer adverse reactions to the cycling process. These are suggestions and just presenting information with my recommendations. Hope no offense is taken.

Sponge filters work as excellent biological filters and work great as main or supplemental filtering. I personally use sponge filters because when I set up a new tank in the future it is very easy to seed it from a sponge filter.

Mike hit some good points. You can cycle a tank with a betta, but you have to be careful (as you should with any fish-in cycle). Just feed lightly, have a test kit on hand at all times, test the water daily, and be ready to do lots of water changes. You don't have to add any other fish.

Shrimp have a rather light bioload, so they won't affect the cycle that much. If you want to make the cycle easier on your little guy I recommend fast-growing plants like water sprite (floating), anarcharis (rooted), and hornwort (rooted). The last two are hit-or-miss for some depending on which exact species you get, but the water sprite is a sure bet. It will also give your little boy some cover under which to sleep and build bubble nests.

I highly recommend a bubble filter over a traditional power filter. Even with buffers some power filters are just too strong for bettas. Bubble filters provide just enough current to move water but won't blow your betta around. I use nothing but bubble filters in my betta tanks.

I don't know how accurate those are. Most of us here use the API Freshwater Master kit. You can also find it at Petsmart. A test kit is a must for a cycle. It is the only way to know when your water is too toxic for your fish and you need to do a water change.

Hi
Does your 5g have a filter? If so I'd say it could be cycled.
Its not advised to add shrimp to a cycling tank. They are more sensitive to poor water conditions then fish. Even a tiny amount of ammonia could result in death. It's best to wait until the tank is stable to add them.
Any size tank can cycle. Even a 1/2g tank will cycle eventually. Smaller tanks are harder to fish in cycle (safely) because ammonia and nitrite reach toxic levels faster then in a larger amount of water.